.shopping {
  box-sizing: border-box;
  padding-top: 40px
}

.shopping .top {
  background-color: #409eff;
  height: 40px;
  line-height: 40px;
  text-align: center;
  color: #fff;
  width: 100%;
  position: fixed;
  left: 0;
  top: 0;
  z-index: 30
}